This invention relates to improvements in methods and apparatus for forming a shoe shank on the bottom of a shoe insole to stiffen the shank region which extends from the heel breast to the ball region. More particularly, the present invention is related to improvements in the method and apparatus described in my copending application Ser. No. 838,670 filed Oct. 3, 1977 and assigned to the assignee of this application. In general, the machine described in said application locates a flexible strip of activatable resinous material on the bottom of an insole and then cures the material directly in situ on the shoe bottom. The strip conforms to the contour of the shoe bottom and forms a rigid shank stiffener which adheres integrally to the insole bottom.
In brief, the apparatus described in my aforementioned prior application includes a shoe jack which supports a shoe assembly, bottom up, so that the insole of the shoe assembly may face a radiant energy source, such as a radiant heater, which is mounted above the shoe jack. Means are provided to locate a shank strip on the bottom of the shoe assembly, and a strip retaining means, in the form of a plurality of finger-like members, is employed to hold the flexible strip against the insole bottom by engaging the longitudinally extending lateral margins of the shank strip. The radiant heater is activated while the shank strip is held by the strip retaining means to cause the shank strip material to cure in situ and form a shank stiffener directly on the bottom of the shoe insole. The resulting shank may, in some instances, terminate rather abruptly at its ball and heel ends which, in some instances, may be undesirable. It is among the general objects of the present invention to provide improvements to the machine and technique described in my prior application by which the ball and heel ends of the shank strip may taper and merge more smoothly with the ball and heel regions of the insole.